:root {
  --container: 1180px;
  --color-primary: #1e3a8a;
  --color-secondary: #3b82f6;
  --color-light: #eff6ff;
  --color-white: #ffffff;
  --color-text: #1f2937;
  --color-border: #e5e7eb;
  --color-success: #10b981;
  --color-warning: #f59e0b;
  --color-danger: #ef4444;
  --spacing-xs: 8px;
  --spacing-sm: 16px;
  --spacing-md: 24px;
  --spacing-lg: 32px;
  --spacing-xl: 48px;
  --spacing-2xl: 64px;
  --transition: all 0.3s ease;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html, body {
  width: 100%;
  height: 100%;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-white);
  overflow-x: hidden;
}

.container {
  width: min(100% - 32px, var(--container));
  margin-inline: auto;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

.image-box,
.board-media,
.tile-media,
.preview-media,
.scenario-media,
.steps-media,
.safety-media {
  overflow: visible;
  line-height: 0;
}

.image-box img,
.board-media img,
.tile-media img,
.preview-media img,
.scenario-media img,
.steps-media img,
.safety-media img {
  max-width: 100%;
  height: auto;
  object-fit: contain;
}

/* Header */
.header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--color-white);
  border-bottom: 1px solid var(--color-border);
  transition: var(--transition);
}

.header.scrolled {
  padding: var(--spacing-sm) 0;
}

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-md) 0;
  margin: 0 auto;
  width: min(100% - 32px, var(--container));
}

.header-left {
  flex: 0 0 auto;
}

.logo-area {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.logo {
  width: 40px;
  height: 40px;
  display: block;
}

.logo-text {
  font-size: 18px;
  font-weight: 600;
  color: var(--color-primary);
}

.header-center {
  flex: 1;
  text-align: center;
  position: relative;
}

.status-text {
  font-size: 14px;
  color: var(--color-text);
}

.progress-indicator {
  position: absolute;
  right: -10px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--color-secondary);
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}

.header-right {
  flex: 0 0 auto;
  display: flex;
  gap: var(--spacing-sm);
}

.header-btn {
  padding: 8px 16px;
  border: 1px solid var(--color-border);
  background: var(--color-white);
  color: var(--color-text);
  border-radius: 4px;
  cursor: pointer;
  font-size: 14px;
  transition: var(--transition);
}

.header-btn:hover {
  border-color: var(--color-secondary);
  background: var(--color-light);
}

.header-btn.active {
  background: var(--color-secondary);
  color: var(--color-white);
  border-color: var(--color-secondary);
}

.progress-bar {
  position: fixed;
  top: 0;
  left: 0;
  height: 2px;
  background: linear-gradient(to right, var(--color-secondary), var(--color-primary));
  width: 0%;
  z-index: 1001;
}

/* Hero */
.hero {
  padding: var(--spacing-2xl) 0;
  background: linear-gradient(135deg, var(--color-light) 0%, var(--color-white) 100%);
}

.hero-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-xl);
  align-items: center;
  margin-bottom: var(--spacing-2xl);
}

.hero-left {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.strategy-label {
  font-size: 13px;
  font-weight: 500;
  color: var(--color-secondary);
  letter-spacing: 0.5px;
}

.hero h1 {
  font-size: 48px;
  line-height: 1.2;
  color: var(--color-primary);
  font-weight: 700;
}

.hero-text {
  font-size: 16px;
  color: var(--color-text);
  line-height: 1.8;
}

.hero-buttons {
  display: flex;
  gap: var(--spacing-md);
  flex-wrap: wrap;
}

.btn {
  padding: 12px 28px;
  border-radius: 6px;
  border: none;
  font-size: 16px;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
}

.btn-primary {
  background: var(--color-secondary);
  color: var(--color-white);
}

.btn-primary:hover {
  background: var(--color-primary);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
}

.btn-secondary {
  background: var(--color-white);
  color: var(--color-secondary);
  border: 2px solid var(--color-secondary);
}

.btn-secondary:hover {
  background: var(--color-light);
  transform: translateY(-2px);
}

.security-tip {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md);
  background: #fef2f2;
  border-left: 3px solid var(--color-danger);
  border-radius: 4px;
  font-size: 14px;
  color: var(--color-text);
}

.tip-icon {
  font-size: 18px;
  flex-shrink: 0;
}

/* Hero Right - Board Panel */
.hero-right {
  position: relative;
}

.board-panel {
  position: relative;
  background: var(--color-white);
  border-radius: 12px;
  overflow: hidden;
  border: 1px solid var(--color-border);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.08);
}

.board-media {
  width: 100%;
  display: block;
}

.board-media img {
  width: 100%;
  height: auto;
}

.board-grid {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-image:
    linear-gradient(0deg, transparent 24%, rgba(59, 130, 246, 0.05) 25%, rgba(59, 130, 246, 0.05) 26%, transparent 27%, transparent 74%, rgba(59, 130, 246, 0.05) 75%, rgba(59, 130, 246, 0.05) 76%, transparent 77%, transparent),
    linear-gradient(90deg, transparent 24%, rgba(59, 130, 246, 0.05) 25%, rgba(59, 130, 246, 0.05) 26%, transparent 27%, transparent 74%, rgba(59, 130, 246, 0.05) 75%, rgba(59, 130, 246, 0.05) 76%, transparent 77%, transparent);
  background-size: 50px 50px;
  pointer-events: none;
  border-radius: 12px;
}

.board-markers {
  position: absolute;
  width: 100%;
  height: 100%;
  top: 0;
  left: 0;
  pointer-events: none;
}

.marker {
  position: absolute;
  width: 60px;
  height: 60px;
  background: rgba(30, 58, 138, 0.8);
  color: var(--color-white);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: 12px;
  border: 2px solid var(--color-white);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

.marker-1 { top: 10%; left: 15%; }
.marker-2 { top: 15%; right: 15%; }
.marker-3 { bottom: 15%; left: 15%; }
.marker-4 { bottom: 10%; right: 15%; }

/* Board Path */
.board-path {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-xl) 0;
  overflow-x: auto;
  flex-wrap: wrap;
}

.path-item {
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--color-light);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  font-size: 14px;
  font-weight: 500;
  white-space: nowrap;
  color: var(--color-primary);
}

.path-arrow {
  color: var(--color-border);
  font-size: 14px;
}

/* Modules */
.module {
  padding: var(--spacing-2xl) 0;
  border-bottom: 1px solid var(--color-border);
}

.module h2 {
  font-size: 32px;
  color: var(--color-primary);
  margin-bottom: var(--spacing-xl);
  text-align: center;
  font-weight: 700;
}

/* Tiles Selector */
.tiles-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-xl);
}

.tile-item {
  padding: var(--spacing-lg);
  background: var(--color-light);
  border: 2px solid var(--color-border);
  border-radius: 12px;
  text-align: center;
  cursor: pointer;
  transition: var(--transition);
}

.tile-item:hover {
  border-color: var(--color-secondary);
  background: var(--color-white);
  transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(59, 130, 246, 0.15);
}

.tile-item.active {
  border-color: var(--color-secondary);
  background: var(--color-secondary);
}

.tile-item.active .tile-name {
  color: var(--color-white);
}

.tile-icon {
  font-size: 36px;
  margin-bottom: var(--spacing-sm);
}

.tile-name {
  font-weight: 600;
  color: var(--color-primary);
  transition: var(--transition);
}

.tiles-content {
  background: var(--color-light);
  border-radius: 12px;
  padding: var(--spacing-xl);
}

.tile-detail {
  display: none;
}

.tile-detail h3 {
  font-size: 24px;
  color: var(--color-primary);
  margin-bottom: var(--spacing-md);
}

.tile-detail p {
  margin-bottom: var(--spacing-md);
  line-height: 1.8;
}

.detail-checklist {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
}

.check-item {
  padding: var(--spacing-sm);
  background: var(--color-white);
  border-radius: 4px;
  font-size: 14px;
  color: var(--color-primary);
}

.tile-media {
  margin-top: var(--spacing-lg);
}

.tile-media img {
  width: 100%;
  height: auto;
  border-radius: 8px;
}

/* Asset Layout */
.layout-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--spacing-lg);
}

.layout-card {
  padding: var(--spacing-lg);
  background: var(--color-light);
  border: 1px solid var(--color-border);
  border-radius: 12px;
  transition: var(--transition);
}

.layout-card:hover {
  border-color: var(--color-secondary);
  background: var(--color-white);
  transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(59, 130, 246, 0.1);
}

.card-header {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-md);
}

.card-coord {
  font-size: 12px;
  font-weight: 700;
  color: var(--color-secondary);
  background: var(--color-white);
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: 4px;
  border: 1px solid var(--color-secondary);
}

.layout-card h3 {
  font-size: 18px;
  color: var(--color-primary);
  flex: 1;
}

.card-status {
  font-size: 12px;
  padding: 4px 8px;
  border-radius: 4px;
  background: rgba(16, 185, 129, 0.1);
  color: var(--color-success);
  white-space: nowrap;
}

.layout-card p {
  margin-bottom: var(--spacing-md);
  color: var(--color-text);
  line-height: 1.7;
}

.card-checklist {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.check-point {
  font-size: 14px;
  color: var(--color-text);
  padding: var(--spacing-sm);
  background: var(--color-white);
  border-radius: 4px;
}

/* Function Board */
.board-layout {
  position: relative;
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-xl);
  margin-bottom: var(--spacing-xl);
}

.board-center {
  width: 200px;
  height: 200px;
  background: linear-gradient(135deg, var(--color-secondary), var(--color-primary));
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto;
  box-shadow: 0 8px 24px rgba(59, 130, 246, 0.3);
}

.center-logo {
  font-size: 24px;
  font-weight: 700;
  color: var(--color-white);
  text-align: center;
}

.board-moves {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-lg);
}

.move-item {
  padding: var(--spacing-lg);
  background: var(--color-light);
  border: 2px solid var(--color-border);
  border-radius: 12px;
  text-align: center;
  cursor: pointer;
  transition: var(--transition);
}

.move-item:hover {
  border-color: var(--color-secondary);
  background: var(--color-white);
  transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(59, 130, 246, 0.15);
}

.move-item.active {
  border-color: var(--color-secondary);
  background: var(--color-secondary);
  box-shadow: 0 8px 24px rgba(59, 130, 246, 0.3);
}

.move-icon {
  font-size: 36px;
  margin-bottom: var(--spacing-sm);
}

.move-label {
  font-weight: 600;
  color: var(--color-primary);
}

.move-item.active .move-label {
  color: var(--color-white);
}

.function-detail {
  display: grid;
  grid-template-columns: 1fr;
}

.detail-item {
  display: none;
  padding: var(--spacing-xl);
  background: var(--color-light);
  border-radius: 12px;
}

.detail-item h3 {
  font-size: 24px;
  color: var(--color-primary);
  margin-bottom: var(--spacing-md);
}

.detail-item p {
  margin-bottom: var(--spacing-lg);
  line-height: 1.8;
}

/* Safety Grid */
.safety-layout {
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: var(--spacing-xl);
}

.safety-lines {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.line-item {
  padding: var(--spacing-md);
  background: var(--color-light);
  border: 2px solid var(--color-border);
  border-radius: 8px;
  cursor: pointer;
  transition: var(--transition);
}

.line-item:hover {
  border-color: var(--color-secondary);
  background: var(--color-white);
  transform: translateX(4px);
}

.line-item.active {
  border-color: var(--color-danger);
  background: var(--color-danger);
}

.line-number {
  font-size: 12px;
  font-weight: 700;
  color: var(--color-secondary);
  margin-bottom: var(--spacing-xs);
}

.line-name {
  font-weight: 600;
  color: var(--color-primary);
}

.line-item.active .line-number,
.line-item.active .line-name {
  color: var(--color-white);
}

.safety-info {
  background: var(--color-light);
  padding: var(--spacing-xl);
  border-radius: 12px;
}

.defense-detail {
  display: none;
}

.defense-detail h3 {
  font-size: 24px;
  color: var(--color-primary);
  margin-bottom: var(--spacing-md);
}

.risk-level {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-md);
  padding-bottom: var(--spacing-md);
  border-bottom: 1px solid var(--color-border);
}

.level-badge {
  padding: 4px 12px;
  border-radius: 4px;
  font-size: 12px;
  font-weight: 600;
  background: var(--color-danger);
  color: var(--color-white);
}

.defense-detail p {
  margin-bottom: var(--spacing-md);
  line-height: 1.8;
}

.defense-detail strong {
  color: var(--color-primary);
}

.safety-media {
  margin-top: var(--spacing-lg);
}

.safety-media img {
  width: 100%;
  height: auto;
  border-radius: 8px;
}

/* App Preview */
.preview-layout {
  display: grid;
  grid-template-columns: 180px 1fr 300px;
  gap: var(--spacing-xl);
  align-items: start;
}

.preview-legend h3 {
  font-size: 18px;
  color: var(--color-primary);
  margin-bottom: var(--spacing-md);
}

.legend-items {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.legend-item {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md);
  background: var(--color-light);
  border: 2px solid var(--color-border);
  border-radius: 8px;
  cursor: pointer;
  transition: var(--transition);
}

.legend-item:hover {
  border-color: var(--color-secondary);
  background: var(--color-white);
}

.legend-item.active {
  border-color: var(--color-secondary);
  background: var(--color-secondary);
}

.legend-num {
  width: 32px;
  height: 32px;
  background: var(--color-secondary);
  color: var(--color-white);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  flex-shrink: 0;
}

.legend-item.active .legend-num {
  background: var(--color-white);
  color: var(--color-secondary);
}

.legend-text {
  font-size: 14px;
  color: var(--color-text);
  font-weight: 500;
}

.legend-item.active .legend-text {
  color: var(--color-white);
}

.preview-main {
  display: flex;
  align-items: center;
  justify-content: center;
}

.phone-frame {
  width: 280px;
  height: 560px;
  background: var(--color-white);
  border: 8px solid var(--color-primary);
  border-radius: 40px;
  overflow: hidden;
  box-shadow: 0 20px 60px rgba(30, 58, 138, 0.3);
  position: relative;
}

.phone-frame::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 26px;
  background: var(--color-primary);
  z-index: 10;
  border-radius: 0 0 20px 20px;
}

.phone-screen {
  width: 100%;
  height: 100%;
  overflow: hidden;
  margin-top: -26px;
  padding-top: 26px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-light);
}

.screenshot-image {
  max-width: 100%;
  max-height: 100%;
  width: auto;
  height: auto;
}

.preview-description {
  padding: var(--spacing-lg);
  background: var(--color-light);
  border-radius: 12px;
}

.desc-item {
  display: none;
}

.desc-item h3 {
  font-size: 18px;
  color: var(--color-primary);
  margin-bottom: var(--spacing-md);
}

.desc-item p {
  font-size: 14px;
  line-height: 1.7;
}

/* Network Steps */
.steps-layout {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-xl);
}

.step-card {
  padding: var(--spacing-lg);
  background: var(--color-light);
  border: 2px solid var(--color-border);
  border-radius: 12px;
  text-align: center;
  cursor: pointer;
  transition: var(--transition);
}

.step-card:hover {
  border-color: var(--color-secondary);
  background: var(--color-white);
  transform: translateY(-4px);
}

.step-card.active {
  border-color: var(--color-secondary);
  background: var(--color-secondary);
}

.step-num {
  font-size: 12px;
  font-weight: 600;
  color: var(--color-secondary);
  margin-bottom: var(--spacing-sm);
}

.step-card.active .step-num {
  color: var(--color-white);
}

.step-icon {
  font-size: 48px;
  margin: var(--spacing-md) 0;
}

.step-card h3 {
  font-size: 18px;
  color: var(--color-primary);
  margin-bottom: var(--spacing-md);
}

.step-card.active h3 {
  color: var(--color-white);
}

.step-card p {
  font-size: 14px;
  line-height: 1.7;
  margin-bottom: var(--spacing-md);
}

.step-requirement {
  display: inline-block;
  padding: 4px 12px;
  background: var(--color-warning);
  color: var(--color-white);
  border-radius: 4px;
  font-size: 12px;
  font-weight: 600;
}

.step-card.active .step-requirement {
  background: rgba(255, 255, 255, 0.3);
}

.arrow-divider {
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 24px;
  color: var(--color-border);
}

.steps-media {
  margin-top: var(--spacing-xl);
}

.steps-media img {
  width: 100%;
  height: auto;
  border-radius: 8px;
}

/* Scenario Guide */
.scenario-layout {
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: var(--spacing-xl);
}

.scenario-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.scenario-item {
  padding: var(--spacing-md);
  background: var(--color-light);
  border: 2px solid var(--color-border);
  border-radius: 8px;
  cursor: pointer;
  transition: var(--transition);
}

.scenario-item:hover {
  border-color: var(--color-secondary);
  background: var(--color-white);
}

.scenario-item.active {
  border-color: var(--color-secondary);
  background: var(--color-secondary);
}

.scenario-question {
  font-size: 14px;
  font-weight: 600;
  color: var(--color-primary);
}

.scenario-item.active .scenario-question {
  color: var(--color-white);
}

.scenario-result {
  background: var(--color-light);
  padding: var(--spacing-xl);
  border-radius: 12px;
}

.result-item {
  display: none;
}

.result-item h3 {
  font-size: 20px;
  color: var(--color-primary);
  margin-bottom: var(--spacing-md);
}

.result-section {
  margin-bottom: var(--spacing-lg);
}

.result-section h4 {
  font-size: 14px;
  color: var(--color-primary);
  margin-bottom: var(--spacing-sm);
  font-weight: 600;
}

.result-section ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.result-section li {
  font-size: 14px;
  padding-left: var(--spacing-md);
  position: relative;
  color: var(--color-text);
}

.result-section li::before {
  content: '•';
  position: absolute;
  left: 0;
  color: var(--color-secondary);
  font-weight: bold;
}

.scenario-media {
  margin-top: var(--spacing-lg);
}

.scenario-media img {
  width: 100%;
  height: auto;
  border-radius: 8px;
}

/* Confirm Grid */
.confirm-items {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-xl);
}

.confirm-card {
  padding: var(--spacing-lg);
  background: var(--color-light);
  border: 2px solid var(--color-border);
  border-radius: 12px;
  text-align: center;
  cursor: pointer;
  transition: var(--transition);
  position: relative;
}

.confirm-card:hover {
  border-color: var(--color-secondary);
  background: var(--color-white);
  transform: translateY(-4px);
}

.confirm-card.confirmed {
  border-color: var(--color-success);
  background: rgba(16, 185, 129, 0.1);
}

.confirm-icon {
  font-size: 36px;
  margin-bottom: var(--spacing-sm);
}

.confirm-label {
  font-weight: 600;
  color: var(--color-primary);
  margin-bottom: var(--spacing-sm);
}

.confirm-check {
  position: absolute;
  top: var(--spacing-sm);
  right: var(--spacing-sm);
  width: 24px;
  height: 24px;
  background: var(--color-success);
  color: var(--color-white);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  opacity: 0;
  transform: scale(0);
  transition: var(--transition);
}

.confirm-card.confirmed .confirm-check {
  opacity: 1;
  transform: scale(1);
}

.confirm-message {
  padding: var(--spacing-lg);
  background: rgba(16, 185, 129, 0.1);
  border: 1px solid var(--color-success);
  border-radius: 8px;
  color: var(--color-success);
  text-align: center;
  font-weight: 600;
  animation: slideInUp 0.5s ease;
}

@keyframes slideInUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

/* FAQ */
.faq-layout {
  display: grid;
  grid-template-columns: 150px 1fr;
  gap: var(--spacing-xl);
}

.faq-categories {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.faq-category {
  padding: var(--spacing-md);
  background: var(--color-light);
  border: 2px solid var(--color-border);
  border-radius: 8px;
  cursor: pointer;
  text-align: center;
  transition: var(--transition);
}

.faq-category:hover {
  border-color: var(--color-secondary);
  background: var(--color-white);
}

.faq-category.active {
  border-color: var(--color-secondary);
  background: var(--color-secondary);
}

.cat-title {
  font-weight: 600;
  color: var(--color-primary);
  margin-bottom: var(--spacing-xs);
}

.faq-category.active .cat-title {
  color: var(--color-white);
}

.cat-icon {
  font-size: 24px;
}

.faq-content {
  background: var(--color-light);
  padding: var(--spacing-xl);
  border-radius: 12px;
}

.faq-group {
  display: none;
}

.faq-group.active {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

.faq-item {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  cursor: pointer;
  transition: var(--transition);
}

.faq-item:hover {
  border-color: var(--color-secondary);
  box-shadow: 0 4px 12px rgba(59, 130, 246, 0.1);
}

.faq-question {
  padding: var(--spacing-lg);
  font-weight: 600;
  color: var(--color-primary);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.faq-question::after {
  content: '▼';
  font-size: 12px;
  color: var(--color-secondary);
  transition: transform 0.3s ease;
}

.faq-item.open .faq-question::after {
  transform: rotate(180deg);
}

.faq-answer {
  display: none;
  padding: 0 var(--spacing-lg) var(--spacing-lg) var(--spacing-lg);
  color: var(--color-text);
  line-height: 1.8;
  border-top: 1px solid var(--color-border);
}

.faq-item.open .faq-answer {
  display: block;
}

.faq-answer p {
  margin-bottom: var(--spacing-sm);
}

/* Footer */
.footer {
  background: var(--color-primary);
  color: var(--color-white);
  padding: var(--spacing-2xl) 0 var(--spacing-lg) 0;
}

.footer-content {
  display: grid;
  grid-template-columns: 1fr 1fr 2fr;
  gap: var(--spacing-xl);
  margin-bottom: var(--spacing-2xl);
}

.footer-left {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: 18px;
  font-weight: 700;
}

.footer-logo img {
  width: 32px;
  height: 32px;
}

.footer-desc {
  font-size: 14px;
  line-height: 1.6;
  opacity: 0.9;
}

.footer-middle {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-xl);
}

.footer-section {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.footer-section h4 {
  font-size: 14px;
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
}

.footer-nav {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.footer-nav a {
  color: var(--color-white);
  text-decoration: none;
  font-size: 14px;
  opacity: 0.9;
  transition: var(--transition);
}

.footer-nav a:hover {
  opacity: 1;
}

.footer-nav li {
  font-size: 14px;
  opacity: 0.9;
}

.footer-right {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.footer-disclaimer {
  font-size: 13px;
  line-height: 1.6;
  opacity: 0.85;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding-top: var(--spacing-lg);
  text-align: center;
  font-size: 13px;
  opacity: 0.8;
}

/* Back to Top */
.back-to-top {
  position: fixed;
  bottom: 40px;
  right: 32px;
  width: 48px;
  height: 48px;
  background: var(--color-secondary);
  color: var(--color-white);
  border: none;
  border-radius: 50%;
  cursor: pointer;
  font-size: 20px;
  display: none;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
  transition: var(--transition);
  z-index: 999;
}

.back-to-top:hover {
  background: var(--color-primary);
  transform: translateY(-4px);
}

.back-to-top.show {
  display: flex;
}

/* Mobile Menu */
.mobile-menu-btn {
  display: none;
  position: fixed;
  bottom: 40px;
  right: 32px;
  width: 56px;
  height: 56px;
  background: var(--color-secondary);
  color: var(--color-white);
  border-radius: 50%;
  cursor: pointer;
  font-size: 24px;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 16px rgba(59, 130, 246, 0.3);
  z-index: 998;
  border: none;
  transition: var(--transition);
}

.mobile-menu-btn:hover {
  background: var(--color-primary);
  transform: scale(1.1);
}

.mobile-menu {
  position: fixed;
  top: 0;
  right: 0;
  width: 280px;
  height: 100vh;
  background: var(--color-white);
  box-shadow: -4px 0 12px rgba(0, 0, 0, 0.15);
  z-index: 999;
  padding: var(--spacing-lg);
  overflow-y: auto;
}

.mobile-menu-close {
  position: absolute;
  top: var(--spacing-lg);
  right: var(--spacing-lg);
  font-size: 24px;
  cursor: pointer;
  color: var(--color-text);
}

.mobile-menu h3 {
  margin-top: var(--spacing-xl);
  margin-bottom: var(--spacing-lg);
  color: var(--color-primary);
  font-size: 18px;
}

.mobile-nav {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.mobile-nav-item {
  padding: var(--spacing-md);
  background: var(--color-light);
  border-radius: 8px;
  text-decoration: none;
  color: var(--color-text);
  border: 1px solid var(--color-border);
  transition: var(--transition);
  display: block;
}

.mobile-nav-item:hover {
  border-color: var(--color-secondary);
  background: var(--color-white);
}

/* Responsive Design */
@media (max-width: 1024px) {
  :root {
    --container: 900px;
  }

  .hero-content {
    grid-template-columns: 1fr;
  }

  .tiles-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .layout-grid {
    grid-template-columns: 1fr;
  }

  .board-moves {
    grid-template-columns: repeat(2, 1fr);
  }

  .safety-layout {
    grid-template-columns: 150px 1fr;
  }

  .preview-layout {
    grid-template-columns: 1fr;
  }

  .phone-frame {
    width: 240px;
    height: 480px;
  }

  .steps-layout {
    grid-template-columns: repeat(2, 1fr);
  }

  .arrow-divider {
    display: none;
  }

  .scenario-layout {
    grid-template-columns: 1fr;
  }

  .confirm-items {
    grid-template-columns: repeat(3, 1fr);
  }

  .faq-layout {
    grid-template-columns: 1fr;
  }

  .faq-categories {
    flex-direction: row;
    flex-wrap: wrap;
  }

  .faq-category {
    flex: 0 0 calc(25% - 12px);
  }

  .footer-content {
    grid-template-columns: 1fr 1fr;
  }

  .footer-middle {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  :root {
    --container: 100%;
    --spacing-xl: 32px;
    --spacing-2xl: 40px;
  }

  .header-container {
    flex-wrap: wrap;
  }

  .header-center {
    flex-basis: 100%;
    order: 3;
    text-align: left;
    font-size: 12px;
    margin-top: var(--spacing-sm);
  }

  .header-right {
    gap: var(--spacing-xs);
  }

  .header-btn {
    padding: 6px 12px;
    font-size: 12px;
  }

  .hero h1 {
    font-size: 32px;
  }

  .hero-text {
    font-size: 14px;
  }

  .hero-buttons {
    flex-direction: column;
  }

  .btn {
    width: 100%;
  }

  .module h2 {
    font-size: 24px;
  }

  .tiles-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .tile-item {
    padding: var(--spacing-md);
  }

  .safety-layout {
    grid-template-columns: 1fr;
  }

  .safety-lines {
    flex-direction: row;
    flex-wrap: wrap;
  }

  .line-item {
    flex: 0 0 calc(33.33% - 11px);
  }

  .preview-layout {
    grid-template-columns: 1fr;
  }

  .preview-legend {
    order: 2;
  }

  .legend-items {
    flex-direction: row;
    flex-wrap: wrap;
  }

  .legend-item {
    flex: 0 0 calc(50% - 8px);
    padding: var(--spacing-sm);
  }

  .legend-num {
    width: 28px;
    height: 28px;
    font-size: 12px;
  }

  .legend-text {
    font-size: 12px;
  }

  .preview-main {
    order: 1;
  }

  .preview-description {
    order: 3;
  }

  .phone-frame {
    width: 200px;
    height: 400px;
  }

  .steps-layout {
    grid-template-columns: 1fr;
  }

  .step-card {
    padding: var(--spacing-md);
  }

  .step-icon {
    font-size: 36px;
  }

  .scenario-list {
    flex-direction: row;
    flex-wrap: wrap;
  }

  .scenario-item {
    flex: 0 0 calc(50% - 8px);
  }

  .scenario-result {
    padding: var(--spacing-lg);
  }

  .confirm-items {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-sm);
  }

  .confirm-card {
    padding: var(--spacing-md);
  }

  .confirm-icon {
    font-size: 28px;
  }

  .confirm-label {
    font-size: 13px;
  }

  .faq-categories {
    flex-direction: row;
    flex-wrap: wrap;
  }

  .faq-category {
    flex: 0 0 calc(50% - 8px);
  }

  .faq-content {
    padding: var(--spacing-lg);
  }

  .faq-question {
    padding: var(--spacing-md);
    font-size: 14px;
  }

  .faq-answer {
    padding: 0 var(--spacing-md) var(--spacing-md) var(--spacing-md);
  }

  .footer-content {
    grid-template-columns: 1fr;
  }

  .footer-middle {
    grid-template-columns: repeat(2, 1fr);
  }

  .mobile-menu-btn {
    display: flex;
  }
}

@media (max-width: 480px) {
  :root {
    --spacing-lg: 20px;
    --spacing-xl: 24px;
    --spacing-2xl: 32px;
  }

  .hero h1 {
    font-size: 24px;
  }

  .hero-text {
    font-size: 13px;
  }

  .module h2 {
    font-size: 20px;
  }

  .tiles-grid {
    grid-template-columns: 1fr;
  }

  .tile-item {
    padding: var(--spacing-md);
  }

  .layout-card {
    padding: var(--spacing-md);
  }

  .board-moves {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-sm);
  }

  .move-item {
    padding: var(--spacing-md);
  }

  .step-card {
    padding: var(--spacing-md);
  }

  .step-card p {
    font-size: 13px;
  }

  .confirm-items {
    grid-template-columns: 1fr;
  }

  .faq-category {
    flex: 0 0 calc(50% - 8px);
    padding: var(--spacing-sm);
  }

  .cat-title {
    font-size: 12px;
  }

  .cat-icon {
    font-size: 18px;
  }

  .faq-question {
    padding: var(--spacing-md);
    font-size: 13px;
  }

  .footer-content {
    grid-template-columns: 1fr;
  }

  .footer-middle {
    grid-template-columns: 1fr;
  }

  .header-btn {
    padding: 6px 10px;
    font-size: 11px;
  }

  .back-to-top {
    width: 44px;
    height: 44px;
    bottom: 32px;
    right: 16px;
  }

  .mobile-menu-btn {
    width: 48px;
    height: 48px;
    bottom: 32px;
    right: 16px;
    font-size: 20px;
  }
}